Nucleating agents are employed as a processing aid primarily to accelerate crystallization from a melt. Other advantages of using nucleating agents include inducing formation of small, uniform-sized spherulites, and reducing mold shrinkage.
Acceleration of crystallization results in faster molding cycles, which of course means greater productivity in molding operations. However, some properties of polyamide resins are altered by the presence of a nucleating agent. For example, when the nucleating agent is sodium phenyl phosphinate (a common polyamide nucleating agent), the Izod impact strength and elongation are adversely affected.